tree-wide: port users over to use new ERRNO_IS_ACCEPT_AGAIN() call

src/activate/activate.c

@@ -271,8 +271,12 @@ static int do_accept(const char* name, char **argv, char **envp, int fd) {
         _cleanup_close_ int fd_accepted = -1;
 
         fd_accepted = accept4(fd, NULL, NULL, 0);
-        if (fd_accepted < 0)
+        if (fd_accepted < 0) {
+                if (ERRNO_IS_ACCEPT_AGAIN(errno))
+                        return 0;
+
                 return log_error_errno(errno, "Failed to accept connection on fd:%d: %m", fd);
+        }
 
         (void) getsockname_pretty(fd_accepted, &local);
         (void) getpeername_pretty(fd_accepted, true, &peer);